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Figure 21 — Relation between Design Speed 

 and Upturn Speed 



characteristic of the modern dry-cargo ship, and this has led to the use of block coefficients 

 lower than the range covered by Series 60. Before leaving the discussion of these data for 

 modern American ships, as given by Mr. de Luce, it is interesting to compare the coverage 

 of Series 60 with actual ship proportions. This has been done in Figures 22, 23, and 24 

 which show the same points as given by de Luce with the addition of the corresponding ones 

 for the Series 60 parents and the limits covered by the whole series. 



In general, the coverage for single-screw ships appears to be adequate, with the 

 exception that some models having a — value of 2.0 would have been a valuable addition 

 to the program. In regard to the LCB variation, the "upturn" speeds for Series 60 occur in 

 general with the LCB somewhat further aft than in the case of the actual designs, but the 

 latter are covered by the limiting models. 



Comparisons between the (C) values for the actual ship models and Series 60 equiva- 

 lents are shown in Figures 25a through 25e. 



The MARINER-Class ships (Figure 25a) differed somewhat in coefficients and propor- 

 tions from the Series 60 parent of 0.60 block coefficient; also, the latter had no bulb at the 

 forefoot. However, the differences were not considered sufficient to justify making an entirely 

 new Series 60 equivalent model. 



V-17 



